QmlDesigenr: Fix jump with mouse wheel zooming

Task-number: QTCREATORBUG-11684
Change-Id: I618bd4454c4677651e0ccfc0cc40ae62c6832a40
Reviewed-by: Alessandro Portale <alessandro.portale@digia.com>

src/plugins/qmldesigner/components/formeditor/zoomaction.cpp

@@ -37,7 +37,7 @@ namespace QmlDesigner {
 ZoomAction::ZoomAction(QObject *parent)
     :  QWidgetAction(parent),
     m_zoomLevel(1.0),
-    m_currentComboBoxIndex(-1)
+    m_currentComboBoxIndex(3)
 {
 
 }